Speaker
Yun Jiang
Description
Axion-like fields with tilted periodic potentials can contain multiple metastable minima. I will discuss how resonant amplification of axion fluctuations can fragment an initially homogeneous field, causing different regions to settle into different vacua without tunneling. Using 3D lattice simulations in an expanding universe, we study the formation, expansion, and collision of these vacuum domains, and show that relativistic collisions can trigger cascades toward lower-energy vacua. This connects axion fragmentation with classical vacuum transitions and may have implications for relaxion models, axion monodromy, and early-universe vacuum selection.